Several olefinic diols of the general formula: ##STR2## in which R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are the same or different alkyl groups, are known. Pure trans diols of the above formula, in which the R groups are the same or different C.sub.1 to C.sub.5 alkyl groups, have been reported to be useful as starting compounds for the synthesis of initiator-transfer agents for cationic polymerization processes.
Of known olefinic diols, butenediol has been described as the only commercially available olefinic diol with primary hydroxyl groups (Kirk-Othmer Encyclopedia of Chemical Technology, 4.sup.th ed., Wiley, 1991, Vol. 1, pages 206-209.) Commercially, the cis isomer of butenediol is almost exclusively formed, although suitable conditions are known to lead to the cis or trans isomers of olefinic-1,4-diols. For example, John R. Johnson and O. H. Johnson, in Journal of the American Chemical Society, Vol. 62 (October 1940), pages 2615-2620, describe the preparation of cis and trans forms of 2,5, dimethyl-3-hexene-2,5-diol. U.S. Pat. No. 5,053,561 (Bender et al, 1991) describes a method for separating the cis and trans isomers of olefinic diols, such as 1,1,4,4-tetraalkyl-2-butene-1,4-diols, by liquid-liquid extraction.